1. Field of the Invention
The invention pertains to arc welding operations manually controlled by a welder. The voltage, current and other parameters of the arc during welding are monitored and visual indicating means located within the helmet worn by the operator visually provide the operator with information to produce high quality and repeatable welds.
2. Description of the Related Art
Semi-automated arc welding is achieved by the welder manually positioning the welding rod or welding wire producing the heat generating arc to the location being welded and such welding operations include stick welding, gas metal arc welding, submerged arc welding and tungsten inert gas welding. These manual welding operations necessarily rely upon the spacing of the electrode from the weld location to produce the desired arc to achieve optimum melting of the base and welding rod or wire metals, and the quality of the weld produced is directly controlled by the skill of the welder.
Skilled manual arc welders rely upon experience to achieve the desired arc, and the operator senses the arc characteristics by the welding sound, light produced and various conditions such as splash, sputtering and the like to determine the quality and effectiveness of the weld. However, even with skilled arc weld operators, it is difficult to manually consistently maintain optimum welding characteristics, and it is very difficult to maintain quality and reliability during manual arc welding procedures. Where high quality welds must be achieved in critical applications, inspections, x-rays, and expensive secondary operations are often necessary significantly adding to the cost of quality arc welding. The cost of identifying and re-working defective arc welds is seven to eight times the cost of the original weldment.
Efforts have been made to provide the manual arc welder with information during welding to improve the quality of the arc. In U.S. Pat. No. 4,677,277, the arc current and voltage is monitored to produce an audio indication to the operator as to the condition of the arc. However, monitors consisting only of audio arc parameter indicators are hard to hear and interpolate and are not capable of achieving the desired closeness of control and quality of weld often required.